(October 28, 2017 at 6:30 pm)Rhondazvous Wrote:(October 28, 2017 at 1:35 pm)c152 Wrote: I don't think that's how light works. Once a photon leaves its star they are separate and the photon will carry on regardless of the fate of what ever source it was created by. That's why, as Cthulhu Dreaming mentioned, it takes time until the last photon from a dying star reaches us and it disappears from our sky. So they aren't connected, the photon and the star, the light of a star is just a continuous stream of photons.You are correct about the last photons leaving the star. They do travel the same distance and take the same amount of time to get here. I'm talking about the photons that are already here. They don't cease to exist. That's why we have the cosmic microwave background. But I do still hold that they cease to be visible light the moment the star dies, just like visible light disappears in a room when you turn the switch off.
And when the star dies its last photons are sent out and it's sort of like unplugging your vacuum cleaner and rolling up the chord, it takes time before the end of the chord reaches the vacuum cleaner. Basically the earth is a vacuum cleaner and stars are just millions of chords that may or may not be rolling up right now and we won't know it until the final photon reaches us.
Bolding mine.
They don't cease to be visible light when the star dies, they cease being visible light when they are absorbed by interactions with matter (i.e. converted to energy).
Same with visible light. Photons are in motion. When those photons leave the light bulb, they emit light until they are absorbed by the walls, etc upon which time they are no longer photons.
